Refrigerating apparatus



Nov. 20, 1934. H. R. LORANGER REFRIGERATING APPARATUS Filed Oct. 25, 1929 W, W? ATTORNEYS Patented Nov. 20, 1934 PATENT OFFICE,

UNITED STATES Frigidaire Corporation, Dayton, Ohio, a corporation of Delaware Application October 25; 1929, Serial No. 402,403

14 Claims.

This invention relates to refrigerating apparatus and particularly to apparatus for returning oil from the evaporator 'to the compressor of a refrigerating system.

One of the objects of the invention is to provide means whereby there is not an excess of oil in the evaporator of a refrigerating system.

Another object of the invention is to provide an,

enclosure for the oil in an evaporator and so associating the enclosure with the structure of the evaporator that any liquid refrigerant within the enclosure will be vaporized.

Another object of the invention is to provide a float inside the evaporator for conveying any liquid lighter than the liquid refrigerant and above any predetermined height to .one of the outlet openings of said evaporator.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawing, wherein a preferred form of the present invention is clearly shown.

In the drawing:

Fig. 1 is a cross section through a preferred form of evaporator disclosing an application of the invention thereto;

Fig; 2 is a cross section through the evaporator on lines 2-2 of Fig. 1;

Fig. 3 is an enlarged cross section through a portion of the float and especially disclosing the passageway therethrough and a preferred form of pivot for the float; I

Fig. 4 is a diagrammatic illustration of a preferred type of refrigerating system, and

Fig. 5 is a partial view of a modification of the invention in Fig. 1.

One of the problems in connection with the refrigerating system is 'that of the circulation through the system of the lubricant supplied to the compressor for its necessary lubrication of moving parts. The vaporized refrigerant is generally drawn to the compressor by suction created by a pumping action in the compressor and on being compressed is forwarded under pressure to the other elements of the refrigerating system. This process of suction compressing and forwarding under pressure is apt to churn the oil into a foamy state and to carry a certain portion of it to other parts of the refrigerating system where it is not desired. Furthermore, as the compressor generally has the pumping action referred to, a certain portion of the oil is mechanically carried along with the refrigerant in addition to that absorbed by the refrigerant. This oil eventually reaches the evaporator and where a refrigerant such as sulphur. dioxide is used the oil will form a blanket on the top of the liquid refrigerant in the eva rator or expander.

If too much oil is drawn from the compressor it may result in the moving parts of the compressor being damaged for want of sufficient lubrication. If the oil blanket becomes very thick on the surface of the liquid refrigerant in the evaporator it decreases the efficiency of the apparatus by taking the place of the liquid refrig- 65 erant and furthermore by hindering the suitable vaporization of the liquid refrigerant. Accordingly it is one of the objectsof this invention toprovide means for returning any excessive oil in the evaporator to the compressor.

It is desired however to prevent any liquid refrigerant from also returning with the oil and causing the frosting over of the conduits between the evaporator and the compressor. When the compressor becomes idle, this frost melts and drips to the floor, with consequent warping or other damage to the floor or its covering. This frosting of the return line also increases the cost of operation due to the loss of efficiency on account of this liquid refrigerant not being evaporated or vaporized in the evaporator.

In Fig. 1 is disclosed atype of evaporator embodying a preferred application of the invention. This evaporator, generally referred to by the numeral 10, is preferably of the flooded float control type such as that disclosed in the patent to R. G. Osborn, 1,556,708 issued October 13, 1925. This evaporator as disclosed has a casing comprising a tank or boiler 11 having a closure or valve plate member 12 about its opening. It is preferred to have a supporting member 13 about the opening of the tank member to receive the fastening means 14 for securing the valve platein position. Suitable sealing gaskets 15 are of course inserted between the two. An inlet valve 95. member 16 is attached to the exterior of the valve plate at the place of entrance of the inlet port 1'7. Surrounding this port 17 in the interior of the evaporator is a needle valve assembly comprising a needle 18 adapted to open and close a very small opening 19. The operation of the needle is controlled by a float ball 20 connected to the needle by a bracket arm 21. On the upper portion of the valve plate is located the outlet valve 22 connected to the outlet port 23 for the vaporized refrigerant.

It is preferred to have one or more housing walls such as the walls 24 form an enclosure or chamber surrounding the outlet port 23 through the valve plate. The liquid refrigerant 25 fills 1 the lower portion of the tank or boiler 11 to a height determined by the calibration of the float ball 20. As this liquid refrigerant, which is preferably sulphur dioxide, vaporizes and fills the upper part of the boiler it is drawn through the housing or enclosure 24 and out through the outlet port 23. To prevent any liquid refrigerant 25 from boiling over into the housing or box 24 a narrow upright chimney or tube 26 is formed on the upper portion of the enclosure 24. It is thus apparent that the gaseous refrigerant return or suction line 31 leading from the interior of the evaporator 10 to the compressor 30 comprises the chimney or tube 26, outlet port 23 and the outlet valve fitting 22 and that the chamber or housing 24 is interposed in this suction line. The walls of the enclosure or chamber 24 where they join the valve plate 12 have a flange 27 welded or soldered to the valve plate so that the walls of the chamber or enclosure 24 are in good thermal conductivity with the valve plate 12. If by any chance any of the liquid refrigerant should enter the enclosure 24, it will rest on the bottom of the enclosure and as the bottom wall is in good thermal conductivity with the valve plate, the liquid refrigerant will be vaporized and will not pass through the outlet port 23 until it has become vaporized. It will be noted that the bottom of the enclosure 24 is preferably below the lower part of the outlet 23.

The vaporized refrigerant passes to a refrigerant liquefying unit, a preferred form of which is illustrated in Fig. '4. A compressor 30 which generally has a pumping action draws the vaporized refrigerant by suction through the outlet 23 and a conduit 31 to the lower portion of the compressor. .The'vaporized refrigerant is then compressed and forwarded under pressure to a condenser 32 where it is liquefied and deposited in the receiver 33 until it is required by the evaporator when it passes up a conduit 34 to the inlet port 17 in the valve plate. The compressor is preferably run by a pulley and belt arrangement 35, 36-and 37 attached to the motor 38. A pressure temperature responsive device 39 of the bellows type controls the snap switch 40 connected in the power mains 41 of the motor. This bellows 39 is preferably connected in the suction line return 31 and governs the running of the. motor 38 in response to the temperature conditions inside the evaporator as is well known.

A considerable quantityof lubricant such as oil is supplied to the compressor 30 for the necessary lubrication of its moving parts. As previously explained, this oil is carried along withthe refrigerant during the operation of the compressor and passes through the condenser and receiver and eventually reaches the evaporator. It is necessary however to return this oil to the compressor.

The problem not only involves the return of the oil itself but the return 'of the oil before the oil blanket reaches a sufiicient thickness on the liquid refrigerant in the evaporator to seriously affect the efliciency of the evaporator. Furthermore, it is also necessary to return the oil without any liquid refrigerant as such liquid" refrigerant will frost the return suction conduit 31, thus causing a decrease in efliciency of the apparatus and also undesirable pools of water on the floor. Accordingly this invention contemplates positive means for returning the oil when it reaches a predetermined height and furthermore insuring that any liquid refrigerant will be evaporated before it passes through the return conduit 31.

As disclosed in Fig. 1 a float assembly as composed of a float 55 is connected by an arm 56 to a pivoted structure 5'7 on the enclosure 24. This float is for the liquid refrigerant and will sink in a lighter liquid. As disclosed in Fig. 3 on an enlarged scale this pivoting structure is preferably attached to the inner end wall of the enclosure 24. A short hollow tube 58 passes through the front of the wall 24 and has a curved flange 59 on the outer end of its short length. A curved tube 60 preferably surrounds the outer portion of this flange so that it can easily pivot thereabout. A cap member 61 is preferably secured to the outer rim of the member 60 as by soldering and is connected to the inner tube opening 62 of the arm 56. This arm 56 has a hollow portion extending for a portion of its length to one or more holes 63. A spring 64 presses against the cap 61 and a washer 65 hearing against the end of the tube 58 to maintain the pivoting structure as tight as possible against leaks.

This float 55 is designed .to float in the liquid refrigerant but will sink in any lighter liquid on the surface of the liquid refrigerant. Accordingly then when the oil blanket 67 is deposited on the surface of the liquid refrigerant 25 the float 55 will sink in the oil but remain floating on the liquid refrigerant. The hole 63 in the arm 56 has been placed at a predetermined height above the surface of the liquid refrigerant 25. This height will generally be less than inch because if the oil blanket becomes thicker than this it will seriously affect the efficiency of the apparatus. Of course the height of this hole could be placed at any predetermined height above the surface of the liquid refrigerant that is desired. In fact it could be close to if not exactly at the height of the liquid refrigerant.

This hole 63 allows a passage therethrough to the chamber or enclosure 24 for any liquid floating on the surface of the liquid refrigerant such as oil. Accordingly any liquid above a desired height above the liquid refrigerant will drain off through the hole 63 into the enclosure 24. As the enclosure 24 is in good thermal contact with the valve plate 12 any liquid refrigerant carried along with this lighter liquid, which is generally oil, will be deposited in the bottom of the enclosurev 24 and have ample time to evaporate before it can pass through the outlet 23. During active bubbling of the liquid refrigerant in the evaporator an oil film will cover the hole 63 and prevent the liquid refrigerant from flowing therethrough. When the boiling is quieted down, the oil will readily flow through the opening 63 and when suflicient oil has been deposited in the enclosure 24 to reach the lower level of the outlet port 23 it will flow therethrough to the valve 22 and down the conduit 31 to the crank case of the compressor.

In case the position of the outlet port 23 for the vaporized gas is not suitable for the direct return of the oil with the vaporized refrigerant in the housing or enclosure 24, a separate oil port 66 as disclosed in Fig. 5 can be provided with a connection 67a therein that can be connected to the conduit 31 or may have an entirely separate conduit back to the compressor. The form of the enclosure formed by the walls 24 as well as the connection of the float thereto is subject to wide variation.

It will be noted that the provision of this float provides means for directly determining the thickness of the oil blanket on the liquid refrigerant. Furthermore, the construction provides ample means for the vaporization of any liquid refrigerant before returning to the compressor. Accord ngly there will not only be a definite thin oil blanket in the evaporator but there will also be no frosting of the return conduits or a decrease in efliciency of the evaporator.

It will also be noted that Figure 4 is purely a diagrammatic illustration of the various elements of the system. The return conduit 31 in actual installations, for example, will not have any depressed portions to form oil traps but will always be sloped more or less downwardly until it reaches the compressor. The connection of the bellows 39 to the return line will also always be made to prevent any oil being trapped therein as by having the bellows above its connection.

While the form of embodiment of the invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. An evaporator comprising a tank adapted to contain liquid'refrigerant, a. closure member for said tank, an enclosure in said tank supported on said closure member and in good thermal conductivity therewith and a float for said refrigerant attached to said enclosure member and having a hole and passage therethrough connected to said enclosure and adapted to convey liquid floating on said liquid refrigerant above a predetermined height to said enclosure, said closure member having an opening therethrough for the egress of said liquid from said evaporator.

2. An evaporator comprising a tank adapted to contain liquid refrigerant, a closure member for said tank, one or more walls having good thermal contact with a portion of said closure member and forming an enclosure supported by said closure member, and a float for said refrigerant adapted to sink in any lighter liquid floating on said refrigerant attached to one of said walls and having a hole and passageway therethrough connected to said enclosure and adapted to convey said lighter liquid above a predetermined height to said enclosure.

3. An evaporator comprising a tank adapted to contain liquid refrigerant, a closure member for said tank, walls forming an enclosure on said closure member and a member connected to said enclosure and floating on said liquid refrigerant and having a passageway therethrough from a predetermined height above the liquid refrigerant to said enclosure.

4. An evaporator comprising a tank adapted to contain liquid refrigerant and a lubricant, a closure member for said tank, one or more walls forming an enclosure on said closure member, an arm loosely attached to said enclosure, a member floating in said refrigerant but sinking in said lubricant on the free endof said arm, said arm having an opening and passageway therethrough to said enclosure for said lubricant.

5. An evaporator comprising a tank adapted to contain liquid refrigerant and a lubricant, a closure member for said tank, one or more walls forming an enclosure on said closure member, an arm pivoted to said enclosure, a member floating in said refrigerant but sinking in said lubricant on the free end of said arm, said arm having an opening and passageway therethrough to said enclosure for said lubricant.

6. In a refrigerating system comprising an evaporator, a compressor, a suction line between the evaporator and the compressor, means for returning lubricant from the evaporator to the compressor comprising a housing inserted in said suction line and provided with a lubricant chamber communicating at its upper portion by means of the suction line with the evaporator and compressor and at its lower portion with the suction line, and means for transferring lubricant from the evaporator into said chamber.

7. In a refrigerating system comprising an evaporator, a compressor, a suction line between the evaporator and the compressor, means for returning lubricant from the evaporator to the compressor comprising a housing inserted in said suction line and provided with a lubricant chamber communicating at its upper portion by means of the suction line with the evaporator and at its lower portion with the suction line, and

means for transferring lubricant from the evaporator into said chamber.

8. In a refrigerating system comprising an evaporator, a compressor, a suction line between the evaporator and the compressor, means for returning lubricant from the evaporator to the compressor comprising a housing inserted in said suction line and provided with a lubricant chamber communicating at its upper portion by means of the suction line with the evaporator and compressor and at its lower portion with the suction line, and a float for transferring lubricant from the evaporator into said chamber.

9. In a refrigerating system comprising an evaporator, a compressor, a suction line between the evaporator and-the compressor, means for returning lubricant from the evaporator to the compressor comprising a housing inserted insaid suction line and provided with a lubricant chamber communicating at its upper portion by means of the suction line with the evaporator and compressor and at its lower portion with the suction line, a float pivotally mounted to a wall of said chamber, and means actuated by said float and communicating with the interior of said chamber for transferring lubricant from the evaporator into said chamber.

10. In a refrigerating system comprising an evaporator, a compressor, a suction line between the evaporator and the compressor, means for returning lubricant from the evaporator to the compressor comprising a housing inserted in said suction line and provided with a lubricant chamber communicating at its upper portion by means of the suction line with the evaporator and compressor and at its lower portion with the suction line, means connected to a wall of said chamber and communicating with the interior thereof for transferring lubricant from the evaporator into said chamber, and a float for actuating said means to control the ingress of lubricant to said means.

11. In a refrigerating system comprising an evaporator, a compressor, a suction line between the evaporator and the compressor, means for returning lubricant from the evaporator to the compressor comprising a housing inserted in said suction line and provided with a lubricant chamber communicating at its upper portion by means of the suction line with the evaporator and compressor and at its lower portion with the suction line, means .pivotally mounted to a wall of said chamber and communicating with the interior thereof for transferring lubricant from the evaporator into said chamber, and a float carried by said pivotally mounted means for actuating same to control the ingress of lubricant thereto. a

12. In a refrigerating system' comprising an compressor comprising a housing inserted in said suction line and provided with a lubricant chamber communicating at its upper portion by means of the suction line with the evaporator and compressor and at its lower portion with the suction line, a conduit secured to a wall of said chamber and communicating with the interior of the chamber for transferring lubricant from the evaporator into said chamber, and a float secured to said conduit for regulating the inlet thereof to control the flow of lubricant from the evaporator to said chamber.

13. In a refrigerating system comprising an evaporator, a compressor, a suction line between the evaporator and the compressor, means for returning lubricant from the evaporator to the compressor comprising a housing inserted in said suction line and provided with a lubricant chamber communicating at its upper portion by means of the suction line with the evaporator and compressor and at its lower portion with the suction line, a conduit having one end thereof pivotally' mounted to a wall of said chamber in open communication with the interior of the chamber for transferring lubricant from the evaporator into said chamber, and a float carried 'by the opposite end of said conduit for regulating the inlet thereof to control the flow of lubricant from the evaporator to said chamber.

14. A refrigerating system comprising an evaporator adapted to contain a body of liquid refrigerant, means for preventing thebody of liquid refrigerant fromrising above a predetermined level, stationary conduit means within the evaporator and leading to the exterior thereof, a second conduit means pivotally connected to and carried by said first conduit means and having a movablei inlet disposed in said evaporator, and means controlled by the level of the body of liquid in said evaporator for maintaining the movable inlet of said second conduit means in substantially constant relation to the body of liquid in the evaporator.

HfiBERT R. LORANGER. 

